Latex comprising colorant and methods of making the same

ABSTRACT

A process includes forming an emulsion comprising a monomer and a colorant, the colorant further including an anionic functional group and a lipophilic counter ion, and polymerizing the monomer to form a latex, the latex includes polymer nanoparticles having the colorant dispersed therein.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of, and claims the benefit of priorityto, U.S. patent application Ser. No. 13/949,195, filed Jul. 23, 2013,the entire contents of which is incorporated herein by reference.

BACKGROUND

Embodiments disclosed herein relate to latexes used in the manufactureof toner particles. More particularly, embodiments disclosed hereinrelate to processes and compositions used for integrating optionallymodified colorants into the matrix of polymer particles in a latex.

Colorants, such as dyes and pigments, employed in toner particlesynthesis are typically added during the aggregation and coalescence(EA/coalescence) of a latex comprising toner particles. Naturalpigments, such as indigo, are potentially useful colorants but are oftendifficult to disperse due to their large particle size and lack offunctionality. These characteristics may also make dispersant attachmentto the pigment particle challenging.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plot showing particle size distribution of latex particlesprepared in accordance with embodiments disclosed herein.

SUMMARY

In some aspects, embodiments disclosed herein relate to processescomprising forming an emulsion comprising a monomer and a colorant, thecolorant further comprising an anionic functional group and a lipophiliccounter ion, and polymerizing the monomer to form a latex, the latexcomprising polymer nanoparticles having the colorant dispersed therein.

In some aspects, embodiments disclosed herein relate to processescomprising forming an emulsion comprising an acrylate monomer, a styrenemonomer, and a colorant comprising a sulfate group and a long chainaliphatic quaternary ammonium counterion, co-polymerizing the acrylateand styrene monomers to form a latex, the latex comprisingstyrene-acrylate co-polymer nanoparticles having the colorant dispersedtherein.

In some aspects, embodiments disclosed herein relate to latexescomprising copolymer nanoparticles having a colorant comprising ananionic functional group and a lipophilic counter ion dispersed within amatrix of the copolymer nanoparticles.

DETAILED DESCRIPTION

Embodiments disclosed herein provide latex emulsions comprising polymerparticles having a colorant or modified colorant dispersed within thepolymer matrix. The latex emulsions may be used in the preparation oftoner particles having colorants efficiently dispersed therein, andobviate the need to introduce the colorants as dispersions duringaggregation/coalescence. Toner particles prepared from thecolorant-containing latexes disclosed herein may provide an overallimproved distribution of colorant throughout the final toner particles.Methods are provided for the preparation of colorant-containing polymerparticles as part of a latex by forming the polymer from a monomeremulsion in the presence of any desired colorants. Without being boundby a particular mechansim, it is believed that the colorants may beencapsulated by the nascent polymer matrix and/or the colorants may beadsorbed into the latex particles once they are formed during thepolymerization step. By way of example, a pigment-based colorant may bepolymer coated during an emulsion polymerization process using asemicontinuous feed maintaining monomer-starved conditions. As will beappreciated by those skilled in the art, the addition of colorants tothe polymerization may change the monomer partitioning as well as thefree radical polymerization kinetics of the reaction which may alter theconcentration of surfactant and monomer employed during polymerization.

The colorant itself may be modified covalently or by ion-exchange withan amine or quaternary ammonium based cationic surfactant prior todoping into monomer feed. Without being bound by theory, it ispostulated that modification of a colorant with a cationic surfactant,for example, may help in suspending the resultant modified colorant inthe monomer solution prior to polymerization, thereby increasing theprobability of monomer coating onto each of the individual colorantparticles. Methods disclosed herein provide nanosized latex particleswhich are readily produced with reduced amounts of surfactant when thecolorant is modified with amine or quaternary ammonium based cationicsurfactant. By way of example, the modification of an indigo pigmentbearing an exchangeable cation can be accomplished by ion exchange ofthe pigment with a long chain alkyl quaternary ammonium salt which alsomay help reduce the particle size of the pigment. The hydrophobic natureof the long chain alkyl group around the colorant particle may alsoenhance polymerization at the colorant surface. Advantageously,modified-colorants disclosed herein may be readily dispersed avoidingthe need for ultrasonic agitation in forming the dispersion. Thus, afine organic dispersion of modified-colorant in monomer may be achievedwith a simple overhead stirrer and/or centrifugal stirrer with noproblems arising from sedimentation or agglomeration of colorantparticles.

The colorant-containing latex particles disclosed herein may be preparedby incorporating one or more colorants into the monomer feed that isused to form the initial seed at the outset of latex production usingconventional emulsion polymerization under starve-fed conditions.Starve-fed emulsion polymerization may be carried out with a totalsolids content in a range from about 10 to about 60 percent by weight ofthe total emulsion mixture. The colorant-monomer feed is thus meteredinto the seeded aqueous medium to provide nanosized generallymonodisperse polymer particles. It will be appreciated that for tonerapplications, monodisperse polymer particles may be particularly useful,however, the polymerization conditions may be altered to provide otherparticle size distributions as needed, such as polydisperse, bidisperse,and the like. Methods disclosed herein can be used to synthesizecolorant-laden polymer particles with a diameter of up to about 200 nmor less in one step, although access to larger particles is possible.Latex particles may be readily synthesized that have characteristics ofgood light stability, bright color and narrow particle sizedistribution. Moreover, incorporation of modified-colorants in thelatexes disclosed herein can be accomplished with minimal reactorfouling. In embodiments, an increased amount of colorant can be used toprovide darker colors, while higher colorant loading may further allowfor reduced amounts of surfactant doping.

Methods disclosed herein are not limited to the production of latexes inconnection with EA toner manufacture. The latexes disclosed herein canalso be used in preparing water-based paints, coatings, cosmetic andhealth/beauty aid products as well. These and other advantages will berecognized by those skilled in the art.

In embodiments, there are provided processes comprising forming anemulsion comprising a monomer and a colorant comprising an anionicfunctional group and a lipophilic counter ion, polymerizing the monomerto form a latex, the latex comprising polymer nanoparticles having thecolorant dispersed therein. In embodiments, forming the latex maycomprise a starve-fed polymerization.

As used herein, “emulsion” refers to a colloidal system in which finedroplets of one liquid are dispersed in another liquid phase where thetwo liquid phases are substantially mutually immiscible.

As used herein, “monomer” is used in accordance with its normal meaningin polymer chemistry as a subunit of a polymer. The term is intended toencompass one or more monomers that make up a polymer used to form alatex.

As used herein, “colorant” refers to both natural and synthetic dyes andpigments. In accordance with embodiments, the colorants may be“modified.” When a colorant is modified, it has been chemically alteredeither by ion exchange or by covalent attachment of a functional moietyon the dye or pigment. In particular embodiments, modified colorants aremodified by introduction of a charge carrying lipophilic group.

As used herein, “anionic functional” group means an organic functionalgroup capable of supporting a negative charge. For example, a carboxylgroup may be ionized to provide a negatively charged carboxylate. Otheranionic functional groups include, without limitation, sulfates,sulfonates, sulfinates, phosphates, and the like.

As used herein, “lipophilic counter ion” refers to any cation or anionhaving substantial hydrophobic character as would be conferred by thepresence of alkyl functional groups, especially one or more long chainalkyl functional groups. Long chain alkyl groups may include at least 6carbon atoms, or at least 8 carbon atoms, or at least 10 carbon atoms.Exemplary lipophilic counter ions include quaternary tetraalkylaminesbearing a net formal charge on nitrogen of +1. In accordance withembodiments disclosed herein, the lipophilic counterions may beintroduced by way of ion exchange of metal ions.

As used herein, “latex” refers to a liquid having polymeric resinparticles dispersed therein. Latexes may be prepared directly fromemulsion polymerization reactions.

As used herein, “nanoparticle” refers to particulate species having aneffective average diameter of about 900 nm or less, or about 700 nm orless, or about 500 nm or less. Nanoparticles need not be perfectlyspherical in nature, although they may be substantially spherical.

In embodiments, the polymer nanoparticles have an average diameter in arange from about 50 nm to about 800 nm, or about 100 nm to about 400 nm,or about 140 nm to about 200 nm. Other particle size ranges and degreesmonodispersity or polydispersity may be accessible by varying thepolymerization conditions, as would be appreciated by those skilled inthe art. In embodiments, the average diameter range may be less than 50nm, including from about 20 nm to about 50 nm. Likewise, averagediameters may also be in a range that exceeds 800 nm, such as about 800to about 1000 nm. Those skilled in the art will recognize that anydesired range of average particle diameters may be accessible by varyingthe emulsion polymerization conditions and that other ranges may besuitable for purposes other than the manufacture of toner particles.

In particular embodiments, there are provided processes comprisingforming an emulsion comprising an acrylate monomer, a styrene monomer,and a colorant comprising a sulfate group and a long chain aliphaticquaternary ammonium counterion, forming a latex from the emulsion, thelatex comprising styrene-acrylate co-polymer nanoparticles having thecolorant dispersed therein. In some such embodiments, a ratio of styreneto acrylate is in a range from about 40:60 to 98:2.

In embodiments, the colorant employed in processes disclosed hereincomprises a modified pigment that is an indigo selected from indigo,isoindigo, indirubin, isoindirubin, 4,4′-dibromo indigo, 6,6′-dibromoindigo, 5,5′-dibromo indigo, cis-6,6′-dibromo indigo,5,5′,7,T-tetrabromo indigo, 4,4′,7,T-tetrachloro indigo, 3H-indol-3-one,1,2-dihydro-2-(3-oxobenzo [b] thien-2-(3H)-ylidene), thioindigo, Vat Red1, cis-thioindigo, 6,6′-dichloro-4,4′-dimethylindigo,5,5′-dichloro-7,T-dimethylindigo, 4,4′-7,7′-tétraméthylindigo,thioindigo Scarlet R, the 2H-indol-2-one, 1,3-dihydro-3-(3-oxobenzo [b]thien-2 (3H)-ylidene)-(3E) thioindirubine, 2H-indol-2-one,1,3-dihydro-3-(2-oxobenzo [b] thiophen-3 (2H)-ylidene), benzo [b]thiophen-2(3H)-one, 3-(2-oxobenzo [b] thiophen-3 (2H)-ylidene, IndigoRussig's Blue, Diosindigo the A, B Diosindigo,4,4′-diethoxy-2,2′-binaphtylidén-I, 1′-dione, 4,4′-bis (hexyloxy)-IH,14H-2,2′-binaphthalene-1,1′-dione, mamegakinone, biramentaceone, andcombinations thereof. A summary of these and other indigos are shown inTable 1 below.

TABLE 1 Indigo

Isoindigo

Indirubine

Isoindirubine

4,4′-dibromo indigo

6,6′-dibromo indigo

5,5′-dibromo indigo

cis-6,6′-dibromo indirubin

5,5′,7,7′- tétrabromo indigo

4,4′,7,7′- tétrachloroindigo

3H-Indol-3-one, 1,2-dihydro-2-(3-oxobenzo[b]thien-2(3H)- ylidene)

Thioindigo (also called: C.I. 73300 C.I. Disperse Red 364 C.I. SolventRed 242 C.I. Vat Red 41 Ciba Pink B Disperse Red 364)

Vat Red 1 (Oralith)

Cis-Thioindigo (Benzo[b]thiophen-3(2H)-one,2-(3-oxobenzo[b]thien-2(3H)-ylidene)-, (2Z))

6,6′-dichloro- 4,4′-diméthylindigo

5,5′-dichloro- 7,7′-diméthylindigo

4,4′,7,7′- tétraméthylindigo

Thioindigo Scarlet R (also known as: 2H-Indol-2-one,1,3-dihydro-3-(3-oxobenzo[b]thien-(3H)- ylidene; C.I. 73635)

2H-Indol-2-one, 1,3-dihydro-3-(3-oxobenzo[b]thien-2(3H)- ylidène)-,(3E)-

Thioindirubine (Benzo[b]thiophen-3(2H)-one,2-(2-oxobenzo[b]thiophen-3(2H)-ylidene))

2H-Indol-2-one, 1,3-dihydro-3-(2-oxobenzo[b]thiophen-3(2H)- ylidene)-

Benzo[b]thiophen-2(3H)-one, 3-(2-oxobenzo[b]thiophen-3(2H)-ylidene)

In embodiments, the modified naturally-derived colorants herein includea modifying component that is an aliphatic quaternary ammonium salt oraromatic quaternary ammonium salt and mixtures thereof and any suitablehalide such as chlorine, bromine or iodine. Suitable N-alkyl/arylcounterions to be used in the modification may be selected from thegroup consisting of quaternary ammonium NH₄, or any alkyl or arylquaternary ammonium, such as tetrabutylammonium, tetraoctylammonium,tetradodecylammonium, tetraoctadecylammonium, N,N-dimethyldioctadecylammonium, N,N-dimethyl dioctyl ammonium, N,N-dimethyl dodecylammonium, N,N,N-trimethyl-1-docosanaminium, behenyl trimethylammonium,N-octadecyltrimethylammonium, and other quaternary ammonium compoundssuch as the quaternary ammonium compounds known as ARQUAD®s availablefrom Akzo Nobel N.V., and mixtures thereof.

The quaternary ammonium compounds known as the ARQUAD®s are primarilyalkyltrimethylammonium chlorides and may be represented by the formulaR—N(CH₃)₃Cl wherein R is a long chain alkyl group having at least 8carbon atoms. These particular quaternary ammonium compounds aremarketed by Akzo Nobel N.V. under the trade-name ARQUAD®. Examples ofsuitable ARQUAD® materials are: Arquad® 316, cocoalkyltrimethylammoniumfrom ARQUAD® C-35, didecydimethylammonium from ARQUAD® 2.10-50, ARQUAD®2.10-70 HFP, 2.10-80, coco(fractionated) dimethylbenzylammonium fromARQUAD® MCB 33, ARQUAD® MCB 50, ARQUAD® MCB 80,hexadecyltrimethylammonium from ARQUAD® 16-29, stearyltrimethylammoniumfrom ARQUAD® 18-50, behenyltrimethylammonium from ARQUAD® 20-80, orsalts thereof. A variety of compounds of this class are availablevarying as to the length and number of long chain alkyl groups attachedto the nitrogen atom. In other embodiments, the N-alkyl or N-arylcounterion is selected from one of the following:

wherein R₁, R₂ and R₃ can be identical or different from one another andwherein each of R₁, R₂ and R₃ is independently selected from the groupconsisting of alkyl, alkoxy, aryl, and alkylaryl and wherein X is anyhalogen atom. In embodiments, the alkyl, alkoxy, aryl, and alkylarylgroups have equal to or greater than 4 carbon atoms. The quaternaryammonium counter ion can also include alkoxylates such as the following:

wherein R is H, CH₃, any alkyl linear or branched, alkoxyl; and whereinm is an integer from 1 to 25 and wherein n is an integer from 1 to 25and wherein, in embodiments m+n is from about 2 to about 25.

Examples include Ethoquad® C/12 wherein R is coco (a complex mixture ofunsaturated and saturated C6 to C18 acids from coconut oil) and whereinm+n=2, Ethoquad® C/25 wherein R is coco and wherein m+n=15, Ethoquad®O/12 wherein R is oleyl and m+n=2, all available from Lion AkzoCorporation.

In embodiments, the quaternary ammonium counter ion herein can be anoligomer of the general formula

wherein n is at least 1. In a specific embodiment, the quaternaryammonium counter ion ispoly[oxy-1,2-ethanediyl(dimethyliminio)-1,2-ethanediyl(dimethyliminio)-1,2-ethanediylchloride(1:2)] (Polixetonium chloride) available from Advantis Technologies,Inc.

Examples of counter ions containing aryl groups include, but are notlimited to, benzyltributylammonium bromide, benzyltributylammoniumchloride, benzyltriethylammonium chloride, benzyltriethylammoniumbromide, benzyltriethylammonium iodide, benzyltrimethylammonium iodide,benzyltrimethylammonium bromide, benzyltrimethylammonium chloride (neator in solution)].

In certain embodiments, the naturally-derived colorant is modified withan aliphatic quaternary ammonium salt comprising an alkyl chain havingat least eight carbon atoms, and, in embodiments, having more than 8carbon atoms.

In other embodiments, the aliphatic quaternary ammonium salt, aromaticquaternary ammonium salt, or a mixture or combination thereof, isbio-based. Bio-based as used herein means that the aliphatic quaternaryammonium salt, an aromatic quaternary ammonium salt, or a mixture orcombination thereof, is derived from natural sources. Bio-basedmaterials are materials that are derived in whole or part from renewablebiomass resources. Biomass resources are organic materials that areavailable on a renewable or recurring basis such as from crop residues,wood residues, grasses, and aquatic plants and as derived from bacteriaand other microorganisms. Corn ethanol is a well-known example of abio-based material derived from biomass resources. A bioproduct is aproduct that contains some amount of biobased material within it.

In other embodiments, the modified naturally-derived colorant ismodified with an aliphatic quaternary ammonium salt, aromatic quaternaryammonium salt, or mixture or combination thereof, that contains an alkylchain having at least 8 carbon atoms, and in embodiments having morethan 8 carbon atoms, wherein the alkyl chain is biobased. Bio-based asused here means that the alkyl chain portion of the aliphatic quaternaryammonium salt, aromatic quaternary ammonium salt, or mixture orcombination thereof is derived from natural sources.

Examples of bio-based quaternary ammonium salts include, but are notlimited to, polyquaternium-4 (hydroxyethyl cellulose dimethyldiallylammonium chloride copolymer), polyquaternium-10 (quaternizedhydroxyethyl cellulose), ARQUAD® PC 268-75 PG (ceteardimonium chlorideand propylene Glycol), ARQUAD® PC C-33W (cocotrimonium chloride),ARQUAD® PC C-35 (cocotrimonium chloride), ARQUAD® PC 2C-75(dicocodimonium chloride (and) isopropyl alcohol), ARQUAD® PC 16-29(cetrimonium chloride), ARQUAD® PC 16-50 (cetrimonium chloride andisopropyl alcohol), ARQUAD® C-33W (cocoalkyl ammonium chloride), ARQUAD®C-50 (cocoalkyl ammonium chloride), ARQUAD® S-50 (soyaalkylammoniumchloride), ARQUAD® T-27W (tallowalkylammonium chloride), ARQUAD® T-50(tallowalkylammonium chloride), ARQUAD® 2C-70 nitritedicocoalkyl-(b)-ammonium chloride), ARQUAD® 2C-70 PG(dicocoalkylammonium chloride), ARQUAD® 2C-75 (dicocoalkylammoniumchloride), ARQUAD® 2HT-75 di(hydrogenated tallowalkyl)ammoniumchloride), ARQUAD® 2HT-75 PG di(hydrogenated tallowalkyl)-(a)-ammoniumchloride), ARQUAD® HTL8 MS 2-ethylhexyl hydrogenatedtallowalkyl-(c)-ammonium chloride), ARQUAD® DMCB-80(benzyldimethyl-cocoalkylammonium chloride), ARQUAD® DMHTB-75(benzyldimethyl-(hydrogenated tallowalkyl)ammonium chloride), ARQUAD®M2HTB (benzylmethyl-di(hydrogenated tallowalkyl)ammonium chloride),ETHOQUAD® C/12B (benzylcocoalkyl[ethoxylated (2)]-ammonium chloride),ETHOQUAD® O/12-75 (cocoalkylmethyl[ethoxylated (2)]-ammonium chloride),ETHOQUAD® O/12 Nitrate (cocoalkylmethyl[ethoxylated (2)]-ammoniumnitrate, ETHOQUAD® C/25 (cocoalkylmethyl[ethoxylated (15)]-ammoniumchloride, ETHOQUAD® O/12 PG (oleylmethyl[ethoxylated (2)]-ammoniumchloride, ETHOQUAD® T/13-27W (tris(2-hydroxyethyl)tallowalkylammoniumacetates, ETHOQUAD® T/25 (tallowalkylmethyl[ethoxylated (15)]-ammoniumchloride, DUOQUAD® T-50(N,N,N′,N′,N′-pentamethyl-N-tallow-1,3-propanediammonium dichloride andthe like and mixtures thereof.

In specific embodiments, the modifying component is a quaternaryammonium salt such as N,N-dimethyldioctadecyl ammoniumbromide.

In specific embodiments, the quaternary ammonium counter ion herein canbe esterquats of the formulae

wherein R is n-heptyl, n-nonyl, n-undecyl, n-tridecyl, n-pentadecyl,n-heptadecyl, n-nonadecyl, n-heneicosyl and mixtures thereof.

Examples of esterquats include, but are not limited to, esterquats suchas those available from Kao Chemicals Inc., quaternary ammonium saltsof: reacted fatty acids, C10-C20 and unsaturated C16-C18, withtriethanolamine (CAS No. 91995-81-2), reacted tallow fatty acids withtriethanolamine (CAS No. 93334-15-7), reacted fatty acids, C12-C20 withtriethanolamine (CAS No. 91032-11-0), reacted 9-octadecenoic acid (Z)with triethanolamine (CAS No. 94095-35-9), reacted octadecenoic acidwith triethanolamine (CAS No. 85408-12-4). Other examples of esterquatsinclude dimethylbis[2-[(1-oxooctadecyl)oxy]ethyl]ammonium chloride (CASNo. 67846-68-8), Dimethylbis[2-[(1-oxohexadecyl)oxy]ethyl]ammoniumchloride (97158-31-1) and(Z)-2-hydroxy-3-[(1-oxo-9-octadecenyl)oxy]propyltrimethylammoniumchloride (CAS No. 19467-38-0).

In other embodiments, quaternary ammonium compounds comprisingalkyltrimethylammonium chlorides represented by the formula R—N(CH₃)₃Clwherein R is a long chain alkyl group having at least 8 carbon atoms canbe selected as the modifying component. A variety of compounds of thisclass are available varying as to the length and number of long chainalkyl groups attached to the nitrogen atom. Certain quaternary ammoniumcompounds are marketed by Akzo Nobel N.V. under the trade-name ARQUAD®such as Arquad® 316. In embodiments, the long chain aliphatic quaternaryammonium counterion comprises at least one unsaturation.

In embodiments, colorant-laden latexes prepared in accordance withmethods disclosed herein are used to form toner particles whcih mayoptionally have a shell-core configuration. In embodiments, the colorladen latex may be used in the shell only, the core only, or in both thecore and the shell. In forming toner particles, the color-laden polymerresin particles of the latex may be formulated with conventionaladditives such as waxes, coagulants, and even further colorants, andsubjected to aggregation with the aid of polyaluminum chloride. Suchaggregation may be carried out with mixing and heating in a controlledmanner to create aggregated particles with a well-defined narrowdistribution of effective diameters. In embodiments, the effectivediameter may be in a range from about 2 to about 6 microns, or about 4to about 6 microns, or about 5 microns. The aggregation may be performedwith the color-laden latex as described herein, or with a latex lackingcolorant. Where the core toner particle latex lacks colorant, processesdisclosed herein include providing a shell latex having the colorantdispersed therein and coalescing the colorant-laden shell latex aboutthe surface of the aggregated particles via heating.

The resultant core-shell toner particle may have an effective diameterin a range of from about 3 microns to about 7 microns, or about 4 toabout 6 microns, or about 5 microns. One skilled in the art willappreciate that the controlled emulsion aggregation/coalescence processallows the user to access toner particles larger or smaller than theserecited ranges if so desired.

In particular embodiments, there are provided latexes comprisingcopolymer nanoparticles having a colorant comprising an anionicfunctional group and a lipophilic counter ion dispersed within a matrixof the copolymer nanoparticles. Such latexes are prepared in accordancewith the methods disclosed herein. In particular embodiments, thecopolymer nanoparticles comprise styrene-acrylate copolymer and thecolorant comprises a modified pigment selected from an indigo, andcombinations thereof. In embodiments, the colorant may be covalentlybound to the matrix. Such covalent bonding motifs may be accessible whenemploying, for example, modified colorants comprising lipophilic groupshaving on or more unsaturations, i.e., alkenes (olefins).

Resin

In embodiments, the monomer comprises a styrene, an acrylate, amethacrylate, a butadiene, an isoprene, an acrylic acid, a methacrylicacid, an acrylonitrile, and combinations thereof. Processes disclosedherein may employ one or more monomers comprising a styrene, anacrylate, a methacrylate, a butadiene, an isoprene, an acrylic acid, amethacrylic acid, an acrylonitrile, and combinations thereof. Anymonomer suitable for preparing a latex for use in a toner may beutilized. As noted above, in embodiments the toner may be produced byemulsion aggregation. Suitable monomers useful in forming a latexpolymer emulsion, and thus the resulting latex particles in the latexemulsion, include, but are not limited to, styrenes, acrylates,methacrylates, butadienes, isoprenes, acrylic acids, methacrylic acids,acrylonitriles, combinations thereof, and the like.

In embodiments, the latex polymer may include at least one polymer. Inembodiments, at least one may be from about one to about twenty and, inembodiments, from about three to about ten. Exemplary polymers includestyrene acrylates, styrene butadienes, styrene methacrylates, and morespecifically, poly(styrene-alkyl acrylate), poly(styrene-1,3-diene),poly(styrene-alkyl methacrylate), poly (styrene-alkyl acrylate-acrylicacid), poly(styrene-1,3-diene-acrylic acid), poly (styrene-alkylmethacrylate-acrylic acid), poly(alkyl methacrylate-alkyl acrylate),poly(alkyl methacrylate-aryl acrylate), poly(aryl methacrylate-alkylacrylate), poly(alkyl methacrylate-acrylic acid), poly(styrene-alkylacrylate-acrylonitrile-acrylic acid), poly(styrene-1,3-diene-acrylonitrile-acrylic acid), poly(alkylacrylate-acrylonitrile-acrylic acid), poly(styrene-butadiene),poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene),poly(ethyl methacrylate-butadiene), poly(propyl methacrylate-butadiene),poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene),poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene),poly(butyl acrylate-butadiene), poly(styrene-isoprene),poly(methylstyrene-isoprene), poly (methyl methacrylate-isoprene),poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene),poly(butyl methacrylate-isoprene), poly(methyl acrylate-isoprene),poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene),poly(butyl acrylate-isoprene), poly(styrene-propyl acrylate),poly(styrene-butyl acrylate), poly (styrene-butadiene-acrylic acid),poly(styrene-butadiene-methacrylic acid), poly(styrene-butadiene-acrylonitrile-acrylic acid), poly(styrene-butylacrylate-acrylic acid), poly(styrene-butyl acrylate-methacrylic acid),poly(styrene-butyl acrylate-acrylononitrile), poly(styrene-butylacrylate-acrylonitrile-acrylic acid), poly(styrene-butadiene),poly(styrene-isoprene), poly(styrene-butyl methacrylate),poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butylmethacrylate-acrylic acid), poly(butyl methacrylate-butyl acrylate),poly(butyl methacrylate-acrylic acid), poly(acrylonitrile-butylacrylate-acrylic acid), and combinations thereof. The polymers may beblock, random, or alternating copolymers.

Colorant

In embodiments, colorants disclosed herein may possess an anionicfunctional group comprising one selected from the group consisting of asulfonate, a carboxylate, a phosphate, and combinations thereof. Inembodiments, the anionic functional group may be paired with alipophilic counter ion that is a quaternary ammonium ion. Inembodiments, a loading of the colorant is in a range from about 0.1 toabout 25 percent by weight, or about 1 to about 15 percent by weight ofthe latex particle composition.

In embodiments, the colorant comprises an indigo. Natural colorants suchas indigo, referenced as C.I. Pigment Blue 66, C.I. Vat Blue 1 and C.I.Reduced Vat Blue 1 (all listed as C.I. 73000) and its derivatives, arealso known as “ancient blues.”

Woad (Indigo) has a structure according to Formula I:

Another woad (indigo) derivative is indirubin, known as (also known asIndigo Red (CAS No. 75790)) and has the structure of Formula II:

Another indigo includes Tyrian Purple which includes compounds ofFormula III and IV below:

The naturally-derived pigment indigo has been derivatized by sulfonationand salting the product in brine, as indicated by compounds of Formula Vand VI below. In accordance with embodiments disclosed herein, sodiumion may be exchanged with a long chain alkyl quaternary ammonium saltwhich has the added benefit of reducint the particle size of thepigment.

Structures V and VI above are known as disodium2-(1,3-dihydro-3-oxo-7-sulphonato-2H-indol-2-ylidene)-3-oxoindoline-5-sulfonate(CAS No. 27414-68-2).

Sulfonated indigo can also comprise multiple sulfonate (SO₃ ⁻) groupssuch as the compounds of Formula VII and VIII below:

Indirubin can also be sulfonated to yield a compound of Formula IX:

This molecule is also known as Indirubin-5-sulfonic acid (CAS No.864131-82-8).

For the further modification of the indigo derivatives, quaternaryammonium salts such as N,N-dimethyldioctadecyl ammoniumbromide andArquad 316 may used; but any mixture of aliphatic, olefinic or aromaticquaternary ammonium salts can be used. The modification of thesulfonated colorants may be carried out in water by heating them withthe desired quaternary ammonium salts. The final product may be isolatedby filtration and washed with copious amounts of water to remove theinorganic salts formed. The structure of exemplary modified colorantsX-XIII are shown below.

The modified colorant-laden latex can be prepared by incorporating themodified pigment in the (organic) monomer phase prior to preparing anoil/water (o/w) emulsion for carrying out the emulsion polymerizationreaction. A seed, which contains the modified colorant and monomers, isadded to the o/w emulsion followed by a conventional emulsionpolymerization process using a semicontinuous feed to maintainmonomer-starved conditions. Regular stirring is used for both thereactor and monomer feed solution which is unlike typical methods whichemploy ultrasonication (i.e., ultrasonically initiated emulsionpolymerization) which is known to increase the probability of monomercoating into individual particles prior to polymerization.

The colorant-laden latex particles may be optionally added to a furthercolorant dispersion. Such further colorant dispersions may include, forexample, submicron colorant particles having a size of, for example,from about 50 to about 500 nanometers in volume average diameter and, inembodiments, of from about 100 to about 400 nanometers in volume averagediameter. The colorant particles may be suspended in an aqueous waterphase containing an anionic surfactant, a nonionic surfactant, orcombinations thereof. In embodiments, the surfactant may be ionic andmay be from about 1 to about 25 percent by weight, and in embodimentsfrom about 4 to about 15 percent by weight, of the colorant.

Colorants useful in forming both latexes and supplemented in formingtoners in accordance with embodiments herein include pigments, dyes,mixtures of pigments and dyes, mixtures of pigments, mixtures of dyes,and the like. The colorant may be, for example, carbon black, cyan,yellow, magenta, red, orange, brown, green, blue, violet, orcombinations thereof. In embodiments a pigment may be utilized. As usedherein, a pigment includes a material that changes the color of light itreflects as the result of selective color absorption. In embodiments, incontrast with a dye which may be generally applied in an aqueoussolution, a pigment generally is insoluble. For example, while a dye maybe soluble in the carrying vehicle (the binder), a pigment may beinsoluble in the carrying vehicle.

In embodiments wherein the colorant is a pigment, the pigment may be,for example, carbon black, phthalocyanines, quinacridones, red, green,orange, brown, violet, yellow, fluorescent colorants including RHODAMINEB™ type, and the like.

The colorant may be present in the toner of the disclosure in an amountof from about 1 to about 25 percent by weight of toner, in embodimentsin an amount of from about 2 to about 15 percent by weight of the toner.

Exemplary colorants include carbon black like REGAL 330® magnetites;Mobay magnetites including MO8029™, MO8060™; Columbian magnetites;MAPICO BLACKS™ and surface treated magnetites; Pfizer magnetitesincluding CB4799™, CB5300™, CB5600™ MCX6369™; Bayer magnetitesincluding, BAYFERROX 8600™, 8610™; Northern Pigments magnetitesincluding, NP-604™, NP-608™; Magnox magnetites including TMB-100™, orTMB-104™, HELIOGEN BLUE L6900™, D6840™, D7080™, D7020™, PYLAM OIL BLUE™,PYLAM OIL YELLOW™, PIGMENT BLUE 1™ available from Paul Uhlich andCompany, Inc.; PIGMENT VIOLET 1™, PIGMENT RED 48™, LEMON CHROME YELLOWDCC 1026™, E.D. TOLUIDINE RED™ and BON RED C™ available from DominionColor Corporation, Ltd., Toronto, Ontario; NOVAPERM YELLOW FGL™,HOSTAPERM PINK E™ from Hoechst; and CINQUASIA MAGENTA™ available fromE.I. DuPont de Nemours and Company. Other colorants include2,9-dimethyl-substituted quinacridone and anthraquinone dye identifiedin the Color Index as CI 60710, CI Dispersed Red 15, diazo dyeidentified in the Color Index as CI 26050, CI Solvent Red 19, coppertetra(octadecyl sulfonamido) phthalocyanine, x-copper phthalocyaninepigment listed in the Color Index as CI 74160, CI Pigment Blue,Anthrathrene Blue identified in the Color Index as CI 69810, SpecialBlue X-2137, diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, amonoazo pigment identified in the Color Index as CI 12700, CI SolventYellow 16, a nitrophenyl amine sulfonamide identified in the Color Indexas Foron Yellow SE/GLN, CI Dispersed Yellow33,2,5-dimethoxy-4-sulfonanilide phenylazo-4′-chloro-2,5-dimethoxyacetoacetanilide, Yellow 180 and Permanent Yellow FGL. Organic solubledyes having a high purity for the purpose of color gamut which may beutilized include Neopen Yellow 075, Neopen Yellow 159, Neopen Orange252, Neopen Red 336, Neopen Red 335, Neopen Red 366, Neopen Blue 808,Neopen Black X53, Neopen Black X55, wherein the dyes are selected invarious suitable amounts, for example from about 0.5 to about 20 percentby weight, in embodiments, from about 5 to about 18 weight percent ofthe toner.

In embodiments, colorant examples include Pigment Blue 15:3 having aColor Index Constitution Number of 74160, Magenta Pigment Red 81:3having a Color Index Constitution Number of 45160:3, Yellow 17 having aColor Index Constitution Number of 21105, and known dyes such as fooddyes, yellow, blue, green, red, magenta dyes, and the like.

In other embodiments, a magenta pigment, Pigment Red 122(2,9-dimethylquinacridone), Pigment Red 185, Pigment Red 192, PigmentRed 202, Pigment Red 206, Pigment Red 235, Pigment Red 269, combinationsthereof, and the like, may be utilized as the colorant. Pigment Red 122(sometimes referred to herein as PR-122) has been widely used in thepigmentation of toners, plastics, ink, and coatings, due to its uniquemagenta shade. The chemical structures of PR-122, Pigment Red 269, andPigment Red 185 (sometimes referred to herein as PR-185) are set forthbelow.

In embodiments, latex formation by emulsion polymerization may becarried out in the presence of other additives selected from the groupconsisting of a crosslinker, a charge control agent, a chain transferagent, a surfactant, and combinations thereof. In embodiments, emulsionpolymerization may be carried out with a seed particle latex. In somesuch embodiments, the seed comprises a colorant in accordance withembodiments disclosed herein. In other embodiments, the seed does notinclude a colorant is functions solely for seeding purposes. Preparing aseed particle latex by aqueous emulsion polymerization of a mixturecomprised of part of the monomer emulsion, from about 0.5 to about 50percent by weight, and preferably from about 3 to about 25 percent byweight of monomer emulsion prepared from pre-reaction monomeremulsification which comprises emulsification of the polymerizationreagents of monomers, chain transfer agent, water, surfactant, andoptional, but preferably an initiator.

Surfactants

In embodiments, the latex may be prepared in an aqueous phase containinga surfactant or co-surfactant. Surfactants which may be utilized withthe polymer to form a latex dispersion can be ionic or nonionicsurfactants, or combinations thereof, in an amount of from about 0.01 toabout 15 weight percent of the solids, in embodiments of from about 0.1to about 10 weight percent of the solids, in embodiments from about 1 toabout 7.5 weight percent solids.

Anionic surfactants which may be utilized include sulfates andsulfonates, sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate, dialkyl benzenealkylsulfates and sulfonates, acids such as abietic acid available fromAldrich, NEOGEN R™, NEOGEN SC™ obtained from Daiichi Kogyo Seiyaku Co.,Ltd., combinations thereof, and the like.

Examples of cationic surfactants include, but are not limited to,ammoniums, for example, alkylbenzyl dimethyl ammonium chloride, dialkylbenzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride,alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammoniumbromide, benzalkonium chloride, C12, C15, C17 trimethyl ammoniumbromides, combinations thereof, and the like. Other cationic surfactantsinclude cetyl pyridinium bromide, halide salts of quaternizedpolyoxyethylalkylamines, dodecylbenzyl triethyl ammonium chloride,MIRAPOL and ALKAQUAT available from Alkaril Chemical Company, SANISOL(benzalkonium chloride), available from Kao Chemicals, combinationsthereof, and the like. In embodiments a suitable cationic surfactantincludes SANISOL B-50 available from Kao Corp., which is primarily abenzyl dimethyl alkonium chloride.

Examples of nonionic surfactants include, but are not limited to,alcohols, acids and ethers, for example, polyvinyl alcohol, polyacrylicacid, methalose, methyl cellulose, ethyl cellulose, propyl cellulose,hydroxyl ethyl cellulose, carboxy methyl cellulose, polyoxyethylenecetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether,polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether,polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether,polyoxyethylene nonylphenyl ether, dialkylphenoxy poly(ethyleneoxy)ethanol, combinations thereof, and the like. In embodiments commerciallyavailable surfactants from Rhone-Poulenc such as IGEPAL CA-210™, IGEPALCA-520™, IGEPAL CA-720™, IGEPAL CO-890™, IGEPAL CO-720™, IGEPAL CO-290™,IGEPAL CA-210™, ANTAROX 890™ and ANTAROX 897™ can be utilized.

The choice of particular surfactants or combinations thereof, as well asthe amounts of each to be used, are within the purview of those skilledin the art.

Initiators

In embodiments initiators may be added for formation of the latexpolymer. Examples of suitable initiators include water solubleinitiators, such as ammonium persulfate, sodium persulfate and potassiumpersulfate, and organic soluble initiators including organic peroxidesand azo compounds including Vazo peroxides, such as VAZO 64™, 2-methyl2-2′-azobis propanenitrile, VAZO 88™, 2-2′-azobis isobutyramidedehydrate, and combinations thereof. Other water-soluble initiatorswhich may be utilized include azoamidine compounds, for example2,2′-azobis(2-methyl-N-phenylpropionamidine) dihydrochloride,2,2′-azobis[N-(4-chlorophenyl)-2-methylpropionamidine] di-hydrochloride,2,2′-azobis[N-(4-hydroxyphenyl)-2-methyl-propionamidine]dihydrochloride,2,2′-azobis[N-(4-amino-phenyl)-2-methylpropionamidine]tetrahydrochloride,2,2′-azobis[2-methyl-N(phenylmethyl)propionamidine]dihydrochloride,2,2′-azobis[2-methyl-N-2-propenylpropionamidine]dihydrochloride,2,2′-azobis[N-(2-hydroxy-ethyl)2-methylpropionamidine]dihydrochloride,2,2′-azobis[2(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride,2,2′-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride,2,2′-azobis[2-(4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl)propane]dihydrochloride,2,2′-azobis[2-(3,4,5,6-tetrahydropyrimidin-2-yl)propane]dihydrochloride,2,2′-azobis[2-(5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl)propane]dihydrochloride,2,2′-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochloride,combinations thereof, and the like.

Initiators can be added in suitable amounts, such as from about 0.1 toabout 8 weight percent of the monomers, in embodiments of from about 0.2to about 5 weight percent of the monomers, in embodiments from about 0.5to about 4 weight percent of the monomers.

Chain Transfer Agents

In embodiments, chain transfer agents may also be utilized in formingthe latex polymer. Suitable chain transfer agents include dodecanethiol, octane thiol, carbon tetrabromide, combinations thereof, and thelike, in amounts from about 0.1 to about 10 percent of monomers, inembodiments from about 0.2 to about 5 percent by weight of monomers, andin embodiments from about 0.5 to about 3.5 percent by weight ofmonomers, to control the molecular weight properties of the latexpolymer when emulsion polymerization is conducted in accordance with thepresent disclosure.

Wax

When forming toner particles, the latex may be added to a wax. Waxdispersions may also be added during formation of a latex polymer in anemulsion aggregation synthesis. Suitable waxes include, for example,submicron wax particles in the size range of from about 50 to about 1000nanometers, in embodiments of from about 100 to about 500 nanometers involume average diameter, suspended in an aqueous phase of water and anionic surfactant, nonionic surfactant, or combinations thereof. Suitablesurfactants include those described above. The ionic surfactant ornonionic surfactant may be present in an amount of from about 0.1 toabout 20 percent by weight, and in embodiments of from about 0.5 toabout 15 percent by weight of the wax.

The wax dispersion according to embodiments of the present disclosuremay include, for example, a natural vegetable wax, natural animal wax,mineral wax, and/or synthetic wax. Examples of natural vegetable waxesinclude, for example, carnauba wax, candelilla wax, Japan wax, andbayberry wax. Examples of natural animal waxes include, for example,beeswax, punic wax, lanolin, lac wax, shellac wax, and spermaceti wax.Mineral waxes include, for example, paraffin wax, microcrystalline wax,montan wax, ozokerite wax, ceresin wax, petrolatum wax, and petroleumwax. Synthetic waxes of the present disclosure include, for example,Fischer-Tropsch wax, acrylate wax, fatty acid amide wax, silicone wax,polytetrafluoroethylene wax, polyethylene wax, polypropylene wax, andcombinations thereof.

Examples of polypropylene and polyethylene waxes include thosecommercially available from Allied Chemical and Baker Petrolite, waxemulsions available from Michelman Inc. and the Daniels ProductsCompany, EPOLENE N-15 commercially available from Eastman ChemicalProducts, Inc., VISCOL 550-P, a low weight average molecular weightpolypropylene available from Sanyo Kasel K.K., and similar materials. Inembodiments, commercially available polyethylene waxes possess amolecular weight (Mw) of from about 100 to about 5000, and inembodiments of from about 250 to about 2500, while the commerciallyavailable polypropylene waxes have a molecular weight of from about 200to about 10,000, and in embodiments of from about 400 to about 5000.

In embodiments, the waxes may be functionalized. Examples of groupsadded to functionalize waxes include amines, amides, imides, esters,quaternary amines, and/or carboxylic acids. In embodiments, thefunctionalized waxes may be acrylic polymer emulsions, for example,JONCRYL 74, 89, 130, 537, and 538, all available from Johnson Diversey,Inc, or chlorinated polypropylenes and polyethylenes commerciallyavailable from Allied Chemical, Baker Petrolite Corporation and JohnsonDiversey, Inc.

The wax may be present in an amount of from about 0.1 to about 30percent by weight, and in embodiments from about 2 to about 20 percentby weight of the toner.

Charge Control Agents

A charge control agent (CCA) may be added to the toner particles. Inembodiments, the CCA may be added to a latex, optional further colorantdispersion, wax, and aggregating agent to incorporate the CCA within thetoner particles. In other embodiments, the CCA may be added once theparticles have formed as part of a shell. The use of a CCA may be usefulfor triboelectric charging properties of a toner, because it may impactthe imaging speed and quality of the resulting toner.

Suitable charge control agents which may be utilized include, inembodiments, metal complexes of alkyl derivatives of acids such assalicylic acid, other acids such as dicarboxylic acid derivatives,benzoic acid, oxynaphthoic acid, sulfonic acids, other complexes such aspolyhydroxyalkanoate quaternary phosphonium trihalozincate, metalcomplexes of dimethyl sulfoxide, combinations thereof, and the like.Metals utilized in forming such complexes include, but are not limitedto, zinc, manganese, iron, calcium, zirconium, aluminum, chromium,combinations thereof, and the like. Alkyl groups which may be utilizedin forming derivatives of salicylic acid include, but are not limitedto, methyl, butyl, t-butyl, propyl, hexyl, combinations thereof and thelike. Examples of such charge control agents include those commerciallyavailable as BONTRON® E-84 and BONTRON® E-88 (commercially availablefrom Orient Chemical). BONTRON® E-84 is a zinc complex of3,5-di-tert-butylsalicylic acid in powder form. BONTRON® E-88 is amixture of hydroxyaluminium-bis[2-hydroxy-3,5-di-tert-butylbenzoate] and3,5-di-tert-butylsalicylic acid. Other suitable CCAs include the calciumcomplex of 3,5-di-tert-butylsalicylic acid, a zirconium complex of3,5-di-tert-butylsalicylic acid, and an aluminum complex of3,5-di-tert-butylsalicylic acid, as disclosed in U.S. Pat. Nos.5,223,368 and 5,324,613, the disclosures of each of which areincorporated by reference in their entirety, combinations thereof, andthe like.

Where utilized, the charge control agent may be present in an amount offrom about 0.01 percent by weight to about 10 percent by weight of thetoner particle, in embodiments from about 0.05 percent by weight toabout 5 percent by weight of the toner particle, in embodiments fromabout 0.1 percent by weight to about 3 percent by weight of the tonerparticle.

Reaction Conditions to Form Toner Particles

In embodiments, methods disclosed herein further comprise forming tonerparticles from the resultant latexes. In the emulsion aggregationprocess, the reactants may be added to a suitable reactor, such as amixing vessel. A blend of latex, optional colorant dispersion, wax, andaggregating agent, may then be stirred and heated to a temperature nearthe Tg of the latex, in embodiments from about 30° C. to about 70° C.,in embodiments from about 40° C. to about 65° C., resulting in toneraggregates of from about 3 microns to about 15 microns in volume averagediameter, in embodiments of from about 5 microns to about 9 microns involume average diameter.

In embodiments, a shell may be formed on the aggregated particles. Anylatex utilized noted above to form the core latex may be utilized toform the shell latex. In embodiments, a styrene-n-butyl acrylatecopolymer may be utilized to form the shell latex. In embodiments, thelatex utilized to form the shell may have a glass transition temperatureof from about 35° C. to about 75° C., in embodiments from about 40° C.to about 70° C. In embodiments, a shell may be formed on the aggregatedparticles including a blend of a first latex for the core and a latexincorporated with a CCA.

Where present, a shell latex may be applied by any method within thepurview of those skilled in the art, including dipping, spraying, andthe like. The shell latex may be applied until the desired final size ofthe toner particles is achieved, in embodiments from about 3 microns toabout 12 microns, in other embodiments from about 4 microns to about 8microns. In other embodiments, the toner particles may be prepared byin-situ seeded semi-continuous emulsion copolymerization of the latexwith the addition of the shell latex once aggregated particles haveformed.

Coagulants

In embodiments, a coagulant may be added during or prior to aggregatingthe latex and the aqueous colorant dispersion. The coagulant may beadded over a period of time from about 1 minute to about 60 minutes, inembodiments from about 1.25 minutes to about 20 minutes, depending onthe processing conditions.

Examples of suitable coagulants include polyaluminum halides such aspolyaluminum chloride (PAC), or the corresponding bromide, fluoride, oriodide, polyaluminum silicates such as polyaluminum sulfo silicate(PASS), and water soluble metal salts including aluminum chloride,aluminum nitrite, aluminum sulfate, potassium aluminum sulfate, calciumacetate, calcium chloride, calcium nitrite, calcium oxylate, calciumsulfate, magnesium acetate, magnesium nitrate, magnesium sulfate, zincacetate, zinc nitrate, zinc sulfate, combinations thereof, and the like.One suitable coagulant is PAC, which is commercially available and canbe prepared by the controlled hydrolysis of aluminum chloride withsodium hydroxide. Generally, PAC can be prepared by the addition of twomoles of a base to one mole of aluminum chloride. The species is solubleand stable when dissolved and stored under acidic conditions if the pHis less than about 5. The species in solution is believed to contain theformula Al₁₃O₄(OH)₂₄(H₂O)₁₂ with about 7 positive electrical charges perunit.

In embodiments, suitable coagulants include a polymetal salt such as,for example, polyaluminum chloride (PAC), polyaluminum bromide, orpolyaluminum sulfosilicate. The polymetal salt can be in a solution ofnitric acid, or other diluted acid solutions such as sulfuric acid,hydrochloric acid, citric acid or acetic acid. The coagulant may beadded in amounts from about 0.01 to about 5 percent by weight of thetoner, and in embodiments from about 0.1 to about 3 percent by weight ofthe toner.

Aggregating Agents

Any aggregating agent capable of causing complexation might be used informing toner of the present disclosure. Both alkali earth metal ortransition metal salts can be utilized as aggregating agents. Inembodiments, alkali (II) salts can be selected to aggregate sodiumsulfonated polyester colloids with a colorant to enable the formation ofa toner composite. Such salts include, for example, beryllium chloride,beryllium bromide, beryllium iodide, beryllium acetate, berylliumsulfate, magnesium chloride, magnesium bromide, magnesium iodide,magnesium acetate, magnesium sulfate, calcium chloride, calcium bromide,calcium iodide, calcium acetate, calcium sulfate, strontium chloride,strontium bromide, strontium iodide, strontium acetate, strontiumsulfate, barium chloride, barium bromide, barium iodide, and optionallycombinations thereof. Examples of transition metal salts or anions whichmay be utilized as aggregating agent include acetates of vanadium,niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron,ruthenium, cobalt, nickel, copper, zinc, cadmium or silver;acetoacetates of vanadium, niobium, tantalum, chromium, molybdenum,tungsten, manganese, iron, ruthenium, cobalt, nickel, copper, zinc,cadmium or silver; sulfates of vanadium, niobium, tantalum, chromium,molybdenum, tungsten, manganese, iron, ruthenium, cobalt, nickel,copper, zinc, cadmium or silver; and aluminum salts such as aluminumacetate, aluminum halides such as polyaluminum chloride, combinationsthereof, and the like. The resulting blend of latex, optionally in adispersion, CCA, optionally in dispersion, optional colorant dispersion,optional wax, optional coagulant, and optional aggregating agent, maythen be stirred and heated to a temperature below the Tg of the latex,in embodiments from about 30° C. to about 70° C., in embodiments of fromabout 40° C. to about 65° C., for a period of time from about 0.2 hoursto about 6 hours, in embodiments from about 0.3 hours to about 5 hours,resulting in toner aggregates of from about 3 microns to about 15microns in volume average diameter, in embodiments of from about 4microns to about 8 microns in volume average diameter.

Once the desired final size of the toner particles is achieved, the pHof the mixture may be adjusted with a base to a value of from about 3.5to about 7, and in embodiments from about 4 to about 6.5. The base mayinclude any suitable base such as, for example, alkali metal hydroxidessuch as, for example, sodium hydroxide, potassium hydroxide, andammonium hydroxide. The alkali metal hydroxide may be added in amountsfrom about 0.1 to about 30 percent by weight of the mixture, inembodiments from about 0.5 to about 15 percent by weight of the mixture.

The mixture of latex, latex incorporated with a CCA, optional colorant,and optional wax may be subsequently coalesced. Coalescing may includestirring and heating at a temperature of from about 80° C. to about 99°C., in embodiments from about 85° C. to about 98° C., for a period offrom about 0.5 hours to about 12 hours, and in embodiments from about 1hour to about 6 hours. Coalescing may be accelerated by additionalstirring.

The pH of the mixture may then be lowered to from about 3.5 to about 6,in embodiments from about 3.7 to about 5.5, with, for example, an acidto coalesce the toner aggregates. Suitable acids include, for example,nitric acid, sulfuric acid, hydrochloric acid, citric acid or aceticacid. The amount of acid added may be from about 0.1 to about 30 percentby weight of the mixture, and in embodiments from about 1 to about 20percent by weight of the mixture.

The mixture is cooled in a cooling or freezing step. Cooling may be at atemperature of from about 20° C. to about 40° C., in embodiments fromabout 22° C. to about 30° C. over a period time from about 1 hour toabout 8 hours, and in embodiments from about 1.5 hours to about 5 hours.

In embodiments, cooling a coalesced toner slurry includes quenching byadding a cooling medium such as, for example, ice, dry ice and the like,to effect rapid cooling to a temperature of from about 20° C. to about40° C., and in embodiments of from about 22° C. to about 30° C.Quenching may be feasible for small quantities of toner, such as, forexample, less than about 2 liters, in embodiments from about 0.1 litersto about 1.5 liters. For larger scale processes, such as for examplegreater than about 10 liters in size, rapid cooling of the toner mixturemay be implemented by the introduction of a heat exchanger when thefinal toner slurry is discharged.

The toner slurry may then be washed. Washing may be carried out at a pHof from about 7 to about 12, and in embodiments at a pH of from about 9to about 11. The washing may be at a temperature of from about 30° C. toabout 70° C., and in embodiments from about 40° C. to about 67° C. Thewashing may include filtering and reslurrying a filter cake includingtoner particles in deionized water. The filter cake may be washed one ormore times by deionized water, or washed by a single deionized waterwash at a pH of about 4 wherein the pH of the slurry is adjusted with anacid, and followed optionally by one or more deionized water washes.

Drying may be carried out at a temperature of from about 35° C. to about75° C., and in embodiments of from about 45° C. to about 60° C. Thedrying may be continued until the moisture level of the particles isbelow a set target of about 1% by weight, in embodiments of less thanabout 0.7% by weight.

Toner particles may possess a CCA, in embodiments a CCA incorporatedinto a latex, in amounts of from about 0.01 percent by weight to about10 percent by weight of the toner particles, in embodiments from about0.1 percent by weight to about 8 percent by weight of the tonerparticles. As noted above, the toner particles may possess CCA latex inthe core, shell, or a combination of both. When in a combination of coreand shell, the ratio of CCA latex in the core to the shell may be fromabout 1:99 to about 99:1, and all combinations in between. Inembodiments, toners of the present disclosure possessing a CCA that hasbeen added during the EA process as a dispersion may have atriboelectric charge of from about −2 μC/g to about −60 μC/g, inembodiments from about −10 μC/g to about −40 μC/g. Toners of the presentdisclosure may also possess a parent toner charge per mass ratio (Q/M)of from about −3 μC/g to about −35 μC/g, and a final toner chargingafter surface additive blending of from −10 μC/g to about −45 μC/g.

Additives

Further optional additives which may be combined with a toner includeany additive to enhance the properties of toner compositions. Includedare surface additives, color enhancers, etc. Surface additives that canbe added to the toner compositions after washing or drying include, forexample, metal salts, metal salts of fatty acids, colloidal silicas,metal oxides, strontium titanates, combinations thereof, and the like,which additives are each usually present in an amount of from about 0.1to about 10 weight percent of the toner, in embodiments from about 0.5to about 7 weight percent of the toner. Examples of such additivesinclude, for example, those disclosed in U.S. Pat. Nos. 3,590,000,3,720,617, 3,655,374 and 3,983,045, the disclosures of each of which arehereby incorporated by reference in their entirety. Other additivesinclude zinc stearate and AEROSIL R972® available from Degussa. Thecoated silicas of U.S. Pat. No. 6,190,815 and U.S. Pat. No. 6,004,714,the disclosures of each of which are hereby incorporated by reference intheir entirety, can also be selected in amounts, for example, of fromabout 0.05 to about 5 percent by weight of the toner, in embodimentsfrom about 0.1 to about 2 percent by weight of the toner. Theseadditives can be added during the aggregation or blended into the formedtoner product.

Toner particles produced utilizing a latex of the present disclosure mayhave a size of about 1 micron to about 20 microns, in embodiments about2 microns to about 15 microns, in embodiments about 3 microns to about 7microns. Toner particles of the present disclosure may have acircularity of from about 0.9 to about 0.99, in embodiments from about0.92 to about 0.98.

Following the methods of the present disclosure, toner particles may beobtained having several advantages compared with conventional toners:(1) increase in the robustness of the particles' triboelectric charging,which reduces toner defects and improves machine performance; (2) easyto implement, no major changes to existing aggregation/coalescenceprocesses; and (3) increase in productivity and reduction in unitmanufacturing cost (UMC) by reducing the production time and the needfor rework (quality yield improvement).

EXAMPLES Example 1 Formation of Styrene/n-Butyl Acrylate Latex Dopedwith “1-Wt % Modified Indigo”

A latex emulsion comprised of polymer particles generated from theemulsion polymerization of styrene, n-butyl acrylate, beta-carboxyethylacrylate (β-CEA) and modified Indigo was prepared as follows. Asurfactant solution of 1.1 grams Dowfax 2A1 (anionic emulsifier; sodiumtetrapropyl diphenyloxide disulfonate, 47 percent active, available fromDow Chemical) and 239.5 grams de-ionized water was prepared by mixingfor 10 minutes in a stainless steel holding tank. The holding tank wasthen purged with nitrogen for 5 minutes before transferring into thereactor. The reactor was then continuously purged with nitrogen whilebeing stirred at 450 rpm. The reactor was then heated up to 80° C. at acontrolled rate, and held there. Separately, 4.0 grams of ammoniumpersulfate initiator was dissolved in 38.2 grams of de-ionized water.

Separately, the monomer emulsion was prepared in the following manner.217 g of styrene, 52.0 g of butyl acrylate, 2.84 modified indigo, 8.1 gof β-CEA, 1.8 g of 1-dodecanethiol, 0.95 g of 1,10-decanediol diacrylate(ADOD), 4.6 g of Dowfax 2A1(anionic surfactant), and 128.3 g ofdeionized water were mixed to form an emulsion. 1% of the above emulsionwas then slowly fed into the reactor containing the aqueous surfactantphase at 80° C. to form the “seeds” while being purged with nitrogen.The initiator solution was then slowly charged into the reactor andafter 10 minutes the rest of the emulsion was continuously fed in usinga metering pump at a rate of 0.5%/min. Once all the monomer emulsion wascharged into the main reactor, the temperature was held at 80° C. for anadditional 2 hours to complete the reaction. Full cooling was thenapplied and the reactor temperature was reduced to 25° C. The productwas collected into a holding tank and sieved with a 25 μm screen.

The particle size was then measured by Nanotrac® U2275E particle sizeanalyzer. The color of the latex was similar to a baby/light blue sinceonly 1-wt % of modified Indigo was used. Narrow particle size wasachieved with a Particle Size=167.4 nm±0.08 nm.

What is claimed is:
 1. A latex comprising copolymer nanoparticles havingan organic colorant comprising an anionic functional group and alipophilic counter ion dispersed within a matrix of the copolymernanoparticles.
 2. The latex of claim 1, wherein the copolymernanoparticles comprise styrene-acrylate copolymer.
 3. The latex of claim2, wherein a ratio of styrene to acrylate is in a range from about 40:60to 98:2.
 4. The latex of claim 1, wherein the organic colorant comprisesa modified pigment that comprises an indigo.
 5. The latex of claim 1,wherein the organic colorant is covalently bound to the matrix of thecopolymer nanoparticles.
 6. The latex of claim 1, wherein the anionicfunctional group is selected from the group consisting of a sulfonate, asulfate, a carboxylate, a phosphate, and combinations thereof.
 7. Thelatex of claim 1, wherein the lipophilic counter ion is a quaternaryammonium ion.
 8. The latex of claim 1 further comprising an additiveselected from the group consisting of a crosslinker, a charge controlagent, a chain transfer agent, a surfactant, and combinations thereof.9. The latex of claim 1, wherein the copolymer nanoparticles have anaverage diameter in a range from about 50 nm to about 800 nm.
 10. Thelatex of claim 1, wherein a loading of the organic colorant is in arange from about 0.1 to about 25 percent by weight of the latex.
 11. Thelatex of claim 1, wherein the organic colorant comprises a modifiedpigment comprises an indigo.
 12. The latex of claim 1, wherein the longchain aliphatic quaternary ammonium counterion comprises at least oneunsaturation of the carbon in the counterion.
 13. A latex comprisingcopolymer nanoparticles having an organic colorant comprising an anionicfunctional group and a lipophilic counter ion dispersed within a matrixof the copolymer nanoparticles and further wherein the copolymernanoparticles comprise polymerized monomers selected from the groupconsisting of a styrene, an acrylate, a methacrylate, a butadiene, anisoprene, an acrylic acid, a methacrylic acid, an acrylonitrile, andcombinations thereof.
 14. A toner comprising toner particles having ashell-core configuration, wherein the core comprises a latex comprisingcopolymer nanoparticles having an organic colorant comprising an anionicfunctional group and a lipophilic counter ion dispersed within a matrixof the copolymer nanoparticles.
 15. The toner of claim 14, wherein thecopolymer nanoparticles comprise polymerized monomers selected from thegroup consisting of a styrene, an acrylate, a methacrylate, a butadiene,an isoprene, an acrylic acid, a methacrylic acid, an acrylonitrile, andcombinations thereof.
 16. The toner of claim 14, wherein the shellcomprises a latex comprising copolymer nanoparticles having an organiccolorant comprising an anionic functional group and a lipophilic counterion dispersed within a matrix of the copolymer nanoparticles.
 17. Thetoner of claim 14 further comprising an additive selected from the groupconsisting of waxes, coagulants, color enhancers, aggregating agents,and mixtures thereof.
 18. The toner of claim 17, wherein the additive ispresent in an amount of from about 0.1 to about 10 weight percent of thetoner.
 19. The toner of claim 14, wherein the toner particles have adiameter in a range of from about 1 micron to about 20 microns.
 20. Thetoner of claim 14, wherein the toner particles have a circularity offrom about 0.9 to about 0.99.